Snap-action switch



June 25, 1946. T, QBSZARNY 2,402,838

SNAP-ACTION SWITCH Filed D80. 31, 1943 Ilsa/alto;

war/Z656 Patented June 25, 1946 SNAP-ACTION SWITCH Thedore Obszarny,Chicago, Ill., assignor to Guardian Electric Manufacturing 00., Chicago,11]., a corporation of Illinois Application December 31, 1943, SerialNo. 516,385

4 Claims.

. 1 This invention relates to the electric switches of the snap-actiontype adapted for rapidly mak-' ing and breaking electric circuits. Morespecifically, my invention is directed to snap-action switches of theblade type adapted for controlling either single or multiple circuit,and wherein the switch includes a moveable member adapted to be actuatedby relatively small or light force to efiect operation thereof.

The present invention is directed to certain novel improvements andrefinements in snapaction switches of the type disclosed Lil). my UnitedStates Letters Patent No. 2,378,784, dated June 19, 1945, wherein theswitch includes an elongated, resilient moveable contact member and acooperating resilient, actuating member, and wherein the free endportion of one of the members is formed with a yoke portion, disposed insurrounding relation to the free end portion of the other member, andwherein the free ends of said members are inter-connected by a resilienttoggle serving to normally urge the free ends of the two members apart.

One of the objects of the present invention is to provide an improvedsnap-action switch of the character indicated wherein the resilienttoggle connection between the movable contact member and the actuatingmember is seated on knife edge fulcrums.

Another object is to provide a novel snapaction switch of the characterindicated which is so constructed and arranged as to precludepossibility of the moveable contact member and actuati'ng memberacquiring a balanced or dead center condition of adjustment, with thecontact of the moveable contact member out of engagement with thecooperating fixed contact.

A further object is to provide an improved snap-action switch of thecharacter indicated which is so constructed as to provide minimumfrictional resistance due to rocking action of the resilient toggle, andwhich is positive and sensitive in operation.

Other objects and advantages of this invention will be apparent from thefollowing description, taken in connection with the accompanying drawingin which: I

Figure 1 is a top plan view of the snap-action switch embodying thepresent invention.

Figure 2 is a side elevational view of the switch.

Figure 3 is a vertical longitudinal section through the switch taken,substantially as indicated at line 3-3 on Figure 1.

Figure 4; is a transverse sectional view through the switch, takensubstantially as indicated at line |4 on Figure 2.

Figure 5 is a fragmentary view, partly in section and partly inelevation, through the resilient toggle connection, taken substantiallyas indicated at line H on Figure 2.

Figure 6 is a fragmentary plan view of the outer end of the actuatingmember.

Figure 7 is an enlarged sectional view, taken substantially as indicatedat line '|1 on Fi ure 6.

Figure 8 is a fragmentary plan view of the outer end of the moveablecontact member.-

Figure 9 is an enlarged sectional view, taken substantially as indicatedat line 9-9 on Figure 8.

The switch construction as represented in the drawing, is of theso-called "stack type wherein two separate electric circuits are adaptedto be controlled by actuation of the switch, and it is manifest that theswitch may be constructed for controlling a single circuit. While I haveshown in the drawing a switch construction wherein the actuating membermust be moved from a normal inoperative position to and beyond an overcenter position for actuating the switch, and upon removal of thepressure on the actuating member the switch again returns to its normal,or initial position of adjustment, it will be apparent that, if desired,the switch may be so arranged so as to require an actuating force formoving the switch from one position to the other and for moving it fromthe latter position to the former position. It is also to be understoodthat the novel characteristics of this invention may be embodied in asnap-action switch of the block type wherein the cooperating blademembers are rigidly mounted at one end on a block of insulatingmaterial, such as represented inFigures 6 and 9 of the drawing of myabove mentioned co-pending application.

The switch as represented in the drawing, includes a pair ofsuperimposed, elongated, relatively rigid, spaced-apart contact bars orfingers, l 0 and II, provided at their outer ends with contact buttonsIlla and lla respectively, and their opposite ends being rigidly mountedin insulated relation to each other, between a plurality of insulatingblocks or wafers, l4.

Mounted between the contact bars Ill and I I is a relatively resilient,elongated, moveable contact member l5, provided at its free end, onopposite sides thereof, with contact buttons l 50 and lib, adapted tocooperate respectively with the contact buttons Ilia and Ila of thecontact bars insulating blocks I4, in spaced insulated relation to thecontact bars Ill and II.

An elongated, stamped yoke member ii, of resilient metal, which forconvenience may be termed the actuating member, is mounted at its.

of the moveable'contact member. The contactbars l and II and themoveable contact memher Ii are provided at their rear end portions withlaterally extending ears or lugs, indicated at Inc, Ilc and lierespectively, to which maybe conveniently connected, as by soldering,con-- ductor wires of the electrical circuits to be controlled by theswitch.

The insulating blocks I 4, together with the switch elements, aswell asthe actuating member I8, are each provided with a pair of longitudinallyspaced-apart aligned apertures, in which are snugly fitted tubularinsulating sleeves I9, so as to positively insulate the rigid contactbars III and II and the moveable switch member Ii, from each other. Theassembly of the various elements, in stack formation on the tubularinsulating sleeves, is adapted to be secured to a convenient mounting bymeans of bolts or screws as indicated at 2|.

As may be seen in Figure 1 of the drawing, the opening lid of the yokeportion of the actuating member I8 is so dimensioned as to permit freemovement of th outer end portion of the moveable contact member Ii andactuating member l8 relatively to each other.

The extreme outer end portion of the moveable contact member Ii isprovided with a projection lid, partially formed by a pair ofspaced-apart longitudinal incisions l is in the extreme end portion ofsaid member, as clearly seen in Figure 8 of the drawing. The projectionlid is formed in upwardly oiiset relation to the main body por-- tion ofthe member Ii, as clearly seen in Figure I89 are preferably locatedsubstantially centrally of the thickness of the respective projectionslid and lid, as shown in Figures 9 and 7 of the draw- The knife edgeslig and Ila of themoveable contact member I! and actuating member II,respectively. constitute abutment shoulders or seats, which serve asfulcrums or axes for the rocking movement of a resilient toggleconnection, which as herein shown, includes a pair of flanged tubulareyelets 22 and 23, disposed in telescopic relation to each other, withtheir flanged ends surrounding the respective projections lid and 18d ofsaid members and seating respectively upon the two sets of knife edgeslig and IE9, of said members. A coil spring 26 surrounds the pair oftubular eyelets and abuts at its opposite ends against the inner facesof the flanges thereof, tending to urge the eyelets apart, and likewisetending to urge the free end portions of the respective members I5 andI8 apart, as seen in Figures 2 and 3 of the drawing.

When force is initially applied to the outer end of the actuating memberI i, for actuating the switch, said member is moved from the positionseen in Figure 2 in the drawing, to the position seen in Figure 3 of thedrawing. For causing such actuation-of the switch it is only necessaryto move said member through and beyond the plane of alignment with theouter free end portion of the moveable contact member Ii. As the memberI8 passes beyond said plane, the moveable contact member Ii is moved byvirtue of the resilient toggle connection, with a snap-action 9 of thedrawing. The portions on opposite sidesof the projection lid are bentupwardly as seen in Figures 8 and 9, in a manner to provide true knifeedge fulcrums, as indicated at Iig, which actually is an edge defined bythe juncture of one of lower face and the end face of the moveablecontact member Ii.

The yoke portion of the actuating member, at the inner edge of theopening adjacent the end oi. moveable member Ii, is provided with aprojection lid, partially formed by a pair of spacedapart longitudinalincisions He, said projection being upwardly offset with respect to themain body of the actuating member, as clearly seen in Figure '7. Similarincisions Iii, in alignment with the side edges of the yoke opening,define portions on opposite "sides of the projection lid which are bentupwardly as seen in Figure '7 to provide true knife edge rockingfulcrums as indicated at l8g, defined by the lower face and said inneredge of the yoke opening of said member to separate the contact buttonslie and I be and cause firm contact engagement of the contact buttonslib and Ila a seen in Figure 3 of the drawing. During such movement ofthe actuating member I8 the coilspring 25 becomes slightly compresseduntil the actuating member Ii approaches alignment with the flexiblecontact member I i, and as the actuating member passes beyond the planeof a free end portion of said member I i, the force of the compressedspring is expended to move the contact member Ii with snap-action to itopposite position of adjustment. When force is removed from theactuating member I8, the switch again assumes a position as seen inFigure 2 of the drawing. As above stated however, the actuating memberI8 may be so constructed and arranged as to cause the switch parts toremain stable in either of its two positions of adjustment asrepresented in Figures 2 and 3 of the drawing, which would necessitateforce being applied to opposite sides of the actuating member for movingthe switch from one position to the other.

It will be apparent that the spring 25 is at all time confined dtelescopic movement of the eyelets and precl, des lateral buckling ofthe spring during such movement. Thus the full balanced pressure of thespring is utilized for effecting the snap-action movement of themoveable contact member I5, and tends to maintain a uniform pressurebetween the contact buttons of the moveable contact member and therespective, fixed contact bars I0 and II. By virtue of the true knifeedge fulcrums constituting seats for the resilient toggle, frictionincident to rocking movement of the toggle is reduced to a minimum andthe toggle i sensitive and responsive to extremely small amounts ofmovement of the actuating member I8, with respect to a moveable contactmember Ii. By actual tests it has been found that when the actuatingmember II is moved at an extremely slow rate of speed, that as itapproaches alignment with the plane of the moveable contact member thatthe snap-action of the switch will occur by further movement of.approximately one thousandth of an inch. Hence it is practically animpossibility to have the actuating member and moveable contact memberacquire a state of balance or dead center relation, with the contactbuttons of the moveable contact member out of engagement with either ofthe cooperating contacts of the fixed contact bar and II. This extremesensitivity of actuation is of utmost importance when the switch is usedfor controlling the operation of certain apparatus. To more clearlyrepresent the true knife edge fulcruming action of the resilient toggleconnection, I have shown diagrammatically in Figures '7 and 9 of thedrawing two sets of dot and dash lines, A and B, designatingrespectively the planes of abutment of the flanges of the respectiveeyelet 23 and 22 at the two opposite positions of snap-action adjustmentof the switch. The lines designated A, corre- 6 in the normalinoperative position of the switch. Although I have herein shown anddescribed a certain preferred embodiment of my invention, manifestly itis capable of modification and rearrangement and adaptation to otherforms of toggle connections without departing from the spirit and scopeof this. invention. I do not. therefore, wish to be understood aslimiting this invention to the precise embodiment herein disspond to theplanes of the abutment face of the flanges of the eyelets when theswitch is in the position of adjustment as seen in Figure 2 of thedrawing, and the line B designate the planes of the abutment face of theflanges of the eyelets when the switch parts assume the position seen inFigure 3 of the drawing.

In the construction disclosed, and as commercially manufactured, themoveable contact member I5 is made of suitable resilient material of.010" and the resilient material for the actuating member I8 is made ofresilient material of .020". It has been found that even with theserelatively thin metals that it is possible without applicant's inventionto have a switch rendered inoperative and defective by acquiring abalanced or dead center balanced condition wherein the contacts of themoveable contact member are out of engagement with both of the contactsof the fixed contact bars I!) and II, at which position all of theelectrical circuits controlled by the switch are open. By virtue of thepresent construction this condition is for all practical purposestotally eliminated.

For certain uses of the snap-action switch embodying the presentinvention, I provide a plug of insulating material 21, at the extremeouter end portion of the actuating member l8, whichv plug is adapted tobe engaged by any suitable element for applying force or pressure to theactuating member for causing the switch to move from the position seenin Figure 2 of the drawing to the position seen in Figure 3 of thedrawing.

To limit the downward movement of the actuating member as seen in Figure2 of the drawing, I provide a relatively rigid, elongated strip ofinsulating material 30, mounted against the upper face of the contactbar H with one end thereof fixedly mounted in the stack assembly withthe insulating blocks l4, so as to become a part of the total assembly.

The outer or free end of the insulating strip is formed with an arcuatenotch 3|, so as to provide clearance for the contact button I la, and toavoid possible interference with the making of proper contact betweenthe contact button I51) and the contact Ila. Said insulating strip 30has the additional function of retaining the switch parts in a conditionof adjustment so as to obtain maximum advantage of the pressure of thespring 25 of the toggle connection for insuring adequate pressurebetween the contact buttons We and Illa closed, except as I may be solimited by the appended claims.

I claim as my invention:

l. In a snap-action switch comprising a fixed contact, an elongated,resilient contact member movable into and out of cooperative engagementwith the fixed contact, an elongated, resilient actuating member, saidmembers extending in the same direction in superimposed relation andbeing mounted at one of their corresponding ends, the other ends of saidmembers being free to move relatively to each other, the free endportion of one of said members being formed as a yoke disposed insurrounding relation to the free end portion of the other member, thefree end portions of each of said members being provided with aprojection, said projections extending toward each other, and resilienttoggle means engagin said projections for normally urging the free endsof said members apart whereby movement of the free end portion of theactuating member through and beyond the plane of the free end of themoveable contact member causes said toggle means to be rocked to effectmovement of said moveable contact member with a snap-action into or outof cooperative engagevment with the fixed contact; the improvementcharacterized by the projection on one of said members being laterallyoffset from the planes of thickness of said one member, and theprovision of abutment shoulders adjacent the projection on each memberto constitute rocking seats for said toggle means, said shoulder of saidone member being formed by a portion bent in the direction of offset ofsaid projection, with the juncture of two contiguous surfaces of saidportion constituting a single knife-edge fulcrum.

2. In a snap-action switch comprising a fixed contact, an elongated,resilient contact member moveable into and out of cooperative engagementwith the fixed contact, an elongated, resilient actuating member, saidmembers extending in the same direction in superimposed relation andbeing mounted at one of their corresponding ends, the other ends of saidmembers being free to move relatively to each other, the free endportion of one of said members being formed as a yoke disposed insurrounding relation to the free end portion of theoth'er member, thefree end portions of each of said members being provided with aprojection, said projections extending toward each other, and resilienttoggle means engaging said projections for normally urging the free endsof said members apart, whereby movement of the free end portion of theactuating member through and beyond the plane of the free end of themoveable contact member causes said toggle means to be rocked to effectmovement of said moveable contact member with a snapaction into or outof cooperative engagement with the fixed contact; the improvementcharacterized by the projection on one of said members bein laterallyoffset from the planes of thickness of said one member, and theprovision of abutment shoulders adjacent the projection on each memberto constitute rocking seats for said toggle 7 means, said shoulder oisaid one member being formed by a portion bent in the direction oi oi!-set-oi' said projection, with the juncture of two contiguous surfaces ofsaid portion constituting a single knii'e-edge fulcrum, disposedintermediate the planes defining the thickness of said P oflsetproiection.

3. In a snap-action switch comprising a fixed contact, an elongated,resilient contact member moveable into and out of cooperative engagementwith the viixed contact, an elongated, resilient actuating member,- saidmembers extending in a free end portion oi the other member.- thefreeend portions of each of said members being provided with aprojection, said projections extending toward each other, and resilienttoggle means engaging said projections for normally urging the free endsof said members'apart, whereby movement of the free end portion of theactuatin end of the moveable contact member causes said toggle means tobe rocked to eflect movement of said moveable, contact member with asnapaction into or out of cooperative engagement with the fixed contact;the improvement characterized by the projections being laterally offsetfrom the planes of thickness of said members, and the provision ofabutment shoulders at opposite sides of each projection to constituterocking seats for the toggle means, said shoulders of the respectivemembers being formed by portions being bent in the direction of oifsetof the projection on the respective members with the juncture of twoconmember through and beyond the plane of the tree a v 4 8- tiguoussuriaces of said heat portions constituting single knife-edge iulcrums.

4. In a snap-action switch comprising a fixed contact, an elongated,resilient contact member moveable into and out of cooperative engagementwith the fixed contact, an elongated, resilient actuating member, saidmember extending in the same direction in superimposed relation andbeing mounted at one of their corresponding ends, the other ends of saidmembers being free to move relatively to each other, the free endportion of one of said members being formed as a yoke disposed'insurrounding relation to the free 'end portion of the other member, thefree end portions 01 each of said members being provided with aprojection, said projections extending toward each other,.and resilienttoggle means engaging said projections for normally urging the free endsof said members apart, whereby'movement or the free end portion of theactuating member through and beyond the plane 01' the free end of themoveable contact member causes said toggle means to be rocked to efiectmovement of said moveable contact member with a snapaction into or outofcooperative engagement with the fixed contact; the improvementcharacterized by the projections being laterally offset from the planesof thickness of said members, and the provision of abutment shoulders atopposite sides of each projection to constitute rocking seats for thetoggle. means, said shoulders of the respective members being formed byportions being bent in the direction of oifset of the projection on therespective members with the juncture of two con tiguous surfaces of saidbent portions constituting single knife-edge fulcrums, disposedintermediate the planes defining the thickness of the offset projectionsof the corresponding members.

THEDORE OBSZARNY.

